It's possible to have pneumonia without a fever, especially for older adults, as they often experience milder symptoms. Some pneumonia patients may have a cough but no mucus to discharge with it. Doctors usually refer to mild cases of pneumonia as walking pneumonia, according to WebMD.
There are many causes of pneumonia, including viruses, fungi and chemicals. Mycoplasma pneumoniae, a bacterial microorganism, is the primary trigger of walking pneumonia, states WebMD. Although mild, walking pneumonia is still a contagious disease. Most individuals are infectious for 10 days or less. Walking pneumonia commonly occurs in the summer and fall, though people can get it in the winter and spring as well.